A matched and controlled longitudinal cohort study of dehydrated human amniotic membrane allograft sheet used as a wraparound nerve bundles in robotic-assisted laparoscopic radical prostatectomy: a puissant adjunct for enhanced potency outcomes

Preclinical and clinical evidence for using perinatal tissue allografts in nerve sparing robot assisted radical prostatectomy to hasten recovery of functional outcomes: a literature review

INTRODUCTION

Localized prostate cancer (PCa) is one of the most common malignancies in the United States. Despite continued refinement of robot assisted radical prostatectomy (RARP) surgical methods, post-surgical erectile dysfunction and urinary incontinence remain significant challenges due to iatrogenic injury of local nervous tissue. Thus, the development of therapeutic strategies, including the use of biologic adjuncts to protect and/or enhance recovery and function of nerves following RARP is of growing interest. Perinatal tissue allografts have been investigated as one such biologic adjunct to nerve sparing RARP. However, knowledge regarding their clinical efficacy in hastening return of potency and continence as well as the potential underpinning biological mechanisms involved remains understudied. Thus, the objective of this literature review was to summarize published basic science and clinical studies supporting and evaluating the use of perinatal allografts for nerve repair and their clinical efficacy as adjuncts to RARP, respectively.

METHODS

The literature as of May 2024 was reviewed non-systematically using PubMed, EMBASE, Scopus, and Web of Science databases. The search terms utilized were "robotic prostatectomy", "prostate cancer", "nerve sparing", "perinatal tissue", "allograft", "potency", and "continence" alone or in combination. All articles were reviewed and judged for scientific merit by authors RP and JM, only peer-reviewed studies were considered.

RESULTS

Eight studies of perinatal tissue allograph use in RARP were deemed worthy of inclusion in this nonsystematic review.

CONCLUSIONS

Incontinence and impotence remain significant comorbidities despite continued advancement in surgical technique. However, basic science research has demonstrated potential neurotrophic, anti-fibrotic, and anti-inflammatory properties of perinatal tissue allografts, and clinical studies have shown that patients who receive an intra-operative prostatic perinatal membrane wrap have faster return to potency and continence.

Impact of Cryopreserved Placental Allografts on Biochemical Recurrence in Prostate Cancer

BACKGROUND

Human placental allografts are widely used to promote wound healing. Placental (or amniotic membrane/umbilical cord) allografts are placed along the neurovascular bundles during radical prostatectomy to improve continence and erectile function recovery. It is unknown whether placental allografts impact biochemical recurrence (BCR).

METHODS

This was a single-surgeon retrospective study of 566 robotic radical prostatectomies performed from April 2015 to March 2021. The patients were divided into three groups: the negative control, Brand A, and Brand B. Brand A and Brand B were both cryopreserved amniotic membrane (CAM) allografts. A total of 324 cases were included for BCR Kaplan-Meier and risk-adjusted multivariate analyses (362 for continence analysis). In vitro analyses were performed to determine the effect of CAM allografts on prostate cancer (PCa) cell line growth.

RESULTS

For propensity score-matched analysis (adjusting for pre-operative PSA, tumor stage, Gleason Grade, and margin status), (1) the allograft groups did not show differences in time to BCR vs. the negative control group (p = 0.7), and (2) combined allograft treatment groups showed better continence recovery vs. the negative controls (p = 0.01). In vitro, placental allografts reduced PCa cell line growth in co-culture assays.

CONCLUSIONS

cryopreserved AM allografts (combined or individual brands) did not show a significant effect on BCR but improved continence recovery for PCa patients.

Navigating Now and Next: Recent Advances and Future Horizons in Robotic Radical Prostatectomy

Robotic-assisted radical prostatectomy (RARP) has become the leading approach for radical prostatectomy driven by innovations aimed at improving functional and oncological outcomes. The initial advancement in this field was transperitoneal multiport robotics, which has since undergone numerous technical modifications. These enhancements include the development of extraperitoneal, transperineal, and transvesical approaches to radical prostatectomy, greatly facilitated by the advent of the Single Port (SP) robot. This review offers a comprehensive analysis of these evolving techniques and their impact on RARP. Additionally, we explore the transformative role of artificial intelligence (AI) in digitizing robotic prostatectomy. AI advancements, particularly in automated surgical video analysis using computer vision technology, are unprecedented in their scope. These developments hold the potential to revolutionize surgeon feedback and assessment and transform surgical documentation, and they could lay the groundwork for real-time AI decision support during surgical procedures in the future. Furthermore, we discuss future robotic platforms and their potential to further enhance the field of RARP. Overall, the field of minimally invasive radical prostatectomy for prostate cancer has been an incubator of innovation over the last two decades. This review focuses on some recent developments in robotic prostatectomy, provides an overview of the next frontier in AI innovation during prostate cancer surgery, and highlights novel robotic platforms that may play an increasing role in prostate cancer surgery in the future.

Oncologic outcomes with and without amniotic membranes in robotic-assisted radical prostatectomy: A propensity score matched analysis

Objective

Placement of human placenta derived grafts during robotic-assisted radical prostatectomy (RARP) hastens the return of continence and potency. The long-term impact on the oncologic outcomes remains to be investigated. Our objective was to determine the oncologic outcomes of patients with dehydrated human amnion chorion membrane (dHACM) at RARP compared to a matched cohort.

Methods

In a referral centre, from August 2013 to October 2019, 599 patients used dHACM in bilateral nerve-sparing RARP. We excluded patients with less than 12 months follow-up, simple prostatectomy, and unilateral nerve-sparing. Patients with dHACM (amnio group) were 529, and were propensity score matched 1:1 to 2465 patients without dHACM (non-amnio group) and a minimum follow-up of 36 months. At the time of RARP, dHACM was placed around the neurovascular bundle in the amnio group. Continuous and categorical variables in matched groups was tested by two-sample Kolmogorov-Smirnov test and Fisher's exact test respectively. Outcomes measured were biochemical recurrence (BCR), adjuvant and salvage therapy rates.

Results

Propensity score matching resulted in two groups of 444 patients. Cumulative incidence functions for BCR did not show a difference between the groups (p=0.3). Patients in the non-amnio group required salvage therapy more frequently than the amnio group, particularly after partial nerve-sparing RARP (6.3% vs. 2.3%, p=0.001). Limitations are the absence of prospective randomization.

Conclusion

The data suggest that using dHACM does not have a negative impact on BCR in patients. Outcomes of cancer specific and overall survival will require follow-up study to increase our understanding of these grafts' impact on prostate cancer biology.

Emerging Strategies for the Biofabrication of Multilayer Composite Amniotic Membranes for Biomedical Applications

The amniotic membrane (AM) is the innermost part of the fetal placenta, which surrounds and protects the fetus. Due to its structural components (stem cells, growth factors, and proteins), AMs display unique biological properties and are a widely available and cost-effective tissue. As a result, AMs have been used for a century as a natural biocompatible dressing for healing corneal and skin wounds. To further increase its properties and expand its applications, advanced hybrid materials based on AMs have recently been developed. One existing approach is to combine the AM with a secondary material to create composite membranes. This review highlights the increasing development of new multilayer composite-based AMs in recent years and focuses on the benefits of additive manufacturing technologies and electrospinning, the most commonly used strategy, in expanding their use for tissue engineering and clinical applications. The use of AMs and multilayer composite-based AMs in the context of nerve regeneration is particularly emphasized and other tissue engineering applications are also discussed. This review highlights that these electrospun multilayered composite membranes were mainly created using decellularized or de-epithelialized AMs, with both synthetic and natural polymers used as secondary materials. Finally, some suggestions are provided to further enhance the biological and mechanical properties of these composite membranes.

Functional Recovery after the Application of Amniotic Tissues and Methylene Blue during Radical Prostatectomy-A Pilot Study

Amniotic tissues and methylene blue (MB) provide the ability for neuroregeneration, and MB enables intraoperative neurostaining. We first combined the techniques to explore a neuroprotective effect on early functional outcomes in a retrospective proof-of-concept trial of 14 patients undergoing radical prostatectomy (RP). The patients were followed up at a median of 13 months, and the continence and potency rates were reported. Early recovery of continence was found after three months. No effect on potency was detected. The findings indicate the feasibility of this tissue-engineering strategy, and justify prospective comparative studies.

Spider silk erectile nerve reconstruction in robot-assisted radical prostatectomy: a first-in-men feasibility analysis

PURPOSE

To investigate the safety and feasibility of spider silk interposition for erectile nerve reconstruction in patients undergoing robotic radical prostatectomy (RARP).

METHODS

The major-ampullate-dragline from Nephila edulis was used for spider silk nerve reconstruction (SSNR). After removal of the prostate with either uni- or bilateral nerve-sparing, the spider silk was laid out on the site of the neurovascular bundles. Data analysis included inflammatory markers and patient reported outcomes.

RESULTS

Six patients underwent RARP with SSNR. In 50% of the cases, only a unilateral nerve-sparing was performed, bilateral nerve-sparing could be performed in three patients. Placement of the spider silk conduit was uneventful, contact of the spider silk with the surrounding tissue was mostly sufficient for a stable connection with the proximal and distal ends of the dissected bundles. Inflammatory markers peaked until postoperative day 1 but stabilized until discharge without any need for antibiotic treatment throughout the hospital stay. One patient was readmitted due to a urinary tract infection. Three patients reported about erections sufficient for penetration after three months with a continuous improvement of erectile function both after bi- and unilateral nerve-sparing with SSNR up to the last follow-up after 18 months.

CONCLUSION

In this analysis of the first RARP with SSNR, a simple intraoperative handling without major complications was demonstrated. While the series provides evidence that SSNR is safe and feasible, a prospective randomized trial with long-term follow-up is needed to identify further improvement in postoperative erectile function due to the spider silk-directed nerve regeneration.

Preparation of human amniotic membrane for transplantation in different application areas

The human amniotic membrane (hAM) is the inner layer of the placenta and plays protective and nutritional roles for the fetus during pregnancy. It contains multiple growth factors and proteins that mediate unique regenerative properties and enhance wound healing in tissue regeneration. Due to these characteristics hAM has been successfully utilized in ophthalmology for many decades. This material has also found application in a variety of additional therapeutic areas. Particularly noteworthy are the extraordinary effects in the healing of chronic wounds and in the treatment of burns. But hAM has also been used successfully in gynecology, oral medicine, and plastic surgery and as a scaffold for in vitro cell culture approaches. This review aims to summarize the different graft preparation, preservation and storage techniques that are used and to present advantages and disadvantages of these methods. It shows the characteristics of the hAM according to the processing and storage methods used. The paper provides an overview of the currently mainly used application areas and raises new application possibilities. In addition, further preparation types like extracts, homogenates, and the resulting treatment alternatives are described.

Nerve spare robot assisted laparoscopic prostatectomy with amniotic membranes: medium term outcomes

INTRODUCTION

dHACM is a source of factors including cytokines that allow anti-inflammatory and proliferative elements to be utilized for wound and ulcer management. We present our experience of using dHACM in a cohort of patients undergoing nerve-sparing (NS) robot-assisted laparoscopic prostatectomy (RALP). Our objective is to investigate the functional and oncological outcomes of NS after placing amniotic or dehydrated human amnion/chorion membrane (dHACM) on preserved neurovascular bundles (NVBs). From 2013 to 2019, our institution performed transperitoneal multi-port da Vinci robotic prostatectomy. The NVBs are spared by releasing their fascial planes posteriorly, followed by an anterior release of the plane at a similar level. Once the retrograde release of the NVB is performed then 599 patients underwent placement of dHACM graft (AmnioFix by MiMedx, Marietta, GA, USA). The graft was cut into two 4 × 1 cm pieces and laid over the NVB as a wrap. In order to inform the urological community of oncological and functional outcomes, we excluded patients with less than 12 months follow up (n = 64), benign prostatic hyperplasia (n = 5), and unilateral NS (n = 1). 529 (88%) patients were included in this study who underwent a partial or full bilateral NS with dHACM. 529 patients were followed-up for a median (IQR) of 42 months (25-89). Demographics include median (IQR) age 57 years (52-62), median preoperative SHIM score of 24 (21-15), and AUASS of 5 (2-11). Full NS was performed in 74% (391/529). Pathological staging was pT2 = 399 (75%), pT3a = 107 (20%), pT3b = 19 (4%) and pT4 = 4 (1%) with N1 = 3 (0.6%). The number of patients with PSM was 86 (16%), and the overall BCR in the entire cohort was 10%. Postoperatively, 434 (82%) were sexually active. Median time to potency was 119 (37-420) days and time to continence was 42 (23-91) days. Regarding full vs partial NS: median post op SHIM score 18 (13-20) vs 15 (6-20), median time to potency 92 (35-365) days vs 184 (42-560) days, and median time to continence 42 (23-91) days vs 44 (30-92) days. Age > 55 vs ≤ 55 years: median post op SHIM score 18 (12-20) vs 15 (10-20), median time to potency 167 days (42-549) vs 80 (35-288) days, and median time to continence 42 (25-116) days vs 42 (29-76) days. In our series the application of amniotic membrane/dHACM has led to acceptable post RALP outcomes. The BCR rate of 10% in addition to the recovery of potency at a median time of 3 months and continence at 6 weeks is an encouraging result of dHACM. Our findings indicate that dHACM allowed for an even faster period for continence recovery which was independent of grade of NS. Future comparative studies may further assess the impact of new amniotic membrane types on the functional and oncological outcomes after RALP.

Impact of human placental derivative allografts on functional and oncological outcomes after radical prostatectomy: a literature review

Post radical prostatectomy (RP) erectile dysfunction and incontinence impacts quality of life for patients. In an objective to hasten the recovery of these functional outcomes, human placental derived allografts laid on neurovascular bundles (NVB) have been investigated. These grafts include amniotic membranes (AM) chorionic membranes (CM) or umbilical cord (UC) allografts. A literature review performed using the MeSH terms "AMNION" OR "CHORION" OR "AMNIOTIC MEMBRANE" OR "UMBILICAL CORD" AND "PROSTATE CANCER" from no specified start date, to April 2022. 163 articles were retrieved, with 149 articles excluded. 14 articles were eligible and analysed. 5 articles were included in this review for an analysis on comparative outcomes. The average return to potency was statistically significant in the intervention groups. Positive surgical margin (PSM) rates showed a higher rate in the control groups. BCR was observed at a lower rate in the interventional group. This review reveals a benefit from human placental allograft's ability to hasten post RP functional recovery, without impacting oncological control.

Canadian Urological Association guideline: Erectile dysfunction

Erectile dysfunction (ED) impacts the wellness and quality of life of millions of Canadians. An evaluation focused on the identification of reversible and irreversible underlying factors is recommended for patients presenting with ED. Through a shared decision-making model framework, the goal of ED treatment is to improve functional outcomes and enhance sexual satisfaction while minimizing adverse effects associated with treatment. Given that ED is assessed and treated by multiple different types of health practitioners, the purpose of this guideline is to provide the best available evidence to facilitate care delivery through a Canadian lens. After a narrative review of ED assessment and treatment for general readership, five key clinical questions relating to priority areas of ED are assessed using the GRADE and evidence-to-decision-making frameworks.

Early return to continence and potency with use of dehydrated human umbilical cord graft at the time of robot-assisted radical prostatectomy: A case study and analysis of relevant literature

INTRODUCTION

Robot-assisted radical prostatectomy often causes damage to the neurovascular bundle which results in erectile dysfunction and urinary incontinence. Recovery may take months; however, dehydrated umbilical cord allografts appear to offer an advantage in terms of a faster return to continence and potency.

CASE PRESENTATION

A 67-year-old male, who presented with intermediate-risk prostate cancer, underwent a bilateral nerve-sparing radical prostatectomy and placement of dehydrated human umbilical cord graft. Four weeks post-prostatectomy, the patient reported minimal stress urinary incontinence and erections with 75% rigidity. Three months post-prostatectomy, the patient noted improved continence and erections with 100% rigidity.

CONCLUSION

To our knowledge, this is the second experience reported in the literature evaluating the use of umbilical cord allograft during robot-assisted radical prostatectomy, with promising results, and it is the first reported case to analyze potency as an outcome.

Cavernous Branched Nerve Regeneration Using Non-Tubular Artificial Nerve Sheets Using Freeze-Dried Alginate Gel Combined With Polyglycolic Acid Mesh in a Rat Model

Introduction

Neuroprotection and neuroregeneration of cavernous nerve plexus by biological/bioengineering solutions may have the potential to maintain erectile function.

Aims

We evaluated the efficacy of a newly developed artificial nerve sheet using freeze-dried alginate (ALG) with polyglycolic acid (PGA) mesh in a rat model. Methods: Bilateral cavernous nerves of male rats were excised to make an approximately 2 mm gap. A piece of the sponge-like freeze-dried sheet created by covalent cross-linking of ALG gel combined with PGA mesh was placed over the gap to cover each stump without any neural anastomosis. We compared erectile functions in the ALG groups with those in the sham group and the bilateral nerve excision group (n = 12, each).

Main Outcome Measures

Main outcome measure was a rat model with cavernous nerve excision.

Results

All rats in the sham group had erection at 63 or 64 days, and mating behavior was confirmed in 10 rats (83.3%) of the sham group at 56 to 62 days. No erection and mating behavior was observed in the excision group. Ten of the 12 (83.3%) rats in the ALG group had a mating behavior and an erection, and the rates of erection and mating behavior were significantly higher in the ALG group than those in the excision group (P < .01, P < .01, respectively). Using a retrograde FluoroGold, the rate of FluoroGold positive pelvic ganglia proximal to the gap at 61 or 62 days was significantly higher in the ALG group than that in the excision group (P = .014).

Conclusion

The results of our animal study have demonstrated that simply filling the cavernous nerve gap using the non-tubular artificial nerve sheets made of ALG with PGA mesh restored erectile function after cavernous nerve excision.

Narita S, Obara T, Ishikawa N, et al. Cavernous Branched Nerve Regeneration Using Non-Tubular Artificial Nerve Sheets Using Freeze-Dried Alginate Gel Combined With Polyglycolic Acid Mesh in a Rat Model. Sex Med 2021;9:100308.

Update review on five top clinical applications of human amniotic membrane in regenerative medicine

Due to the increasing number of studies performed in the field of regenerative medicine during the last two decades, more analytic studies are still needed to clarify the future prospect of this area of science. The main aim of this research was to review the clinical applications of human Amniotic membrane in the field of regenerative medicine critically. Furthermore, in the light of increasing numbers of available products derived from amniotic membrane, we aimed look in depth to see whether regenerative medicine research strategies have a place in the clinical setting. More specifically, in the present study, we attempted to provide insight on developing the new indication for more research and in the next step, for market leaders companies to expand cost-effectiveness of new derived AM products. 20 companies or distributers have offered some commercial products in this field. Survey on more than 90 clinical trials in last five years showed dermatology (and more specific wound healing), orthopedic, and ophthalmology are heavily biased toward multibillion dollar industry. Moreover, urology and dentistry with fewer numbers of clinical data in comparison with the above-mentioned areas, currently are in the path of translation (especially dentistry). In addition, otolaryngology and oncology with the lowest number showed more potential of research thorough understanding the properties that will help guiding the use of AM-derived products in these two areas in future. More than 50% of clinical studies were done or are developing in USA, which have the biggest share in market products. Subsequently, China, Egypt, India, Iran, and Germany with the ongoing clinical trials in different phases may have more approved products in near future.

Application of Dried Human Amnion Graft to Improve Post-Prostatectomy Incontinence and Potency: A Randomized Exploration Study Protocol

Introduction

Incontinence (up to 20%) and erectile dysfunction (up to 70%) occur frequently after radical prostatectomy (RP) in patients with localized prostate cancer. Human amniotic membrane (HAM) can improve tissue regeneration and functional outcome after RP owing to the growth factors and unique immune tolerance. Preliminary studies showed the potential value of HAM in the reconstruction of the urinary tract and nerve protection during RP.

Methods

A protocol is developed for a prospective, randomized, single-blind, single-surgeon, placebo-controlled exploration study of the efficacy and safety of dehydrated human amnion membrane placed around the neurovascular bundle (NVB) and vesicourethral anastomosis (VUA) during RP for the treatment of localized prostate cancer. Eligible for inclusion are patients with localized prostate cancer, requiring a surgical procedure and exclusion of preoperative incontinence and erectile dysfunction. The patients are randomized 1:1 to HAM vs. placebo and blinded during the study period. According to the T test with an alpha of 0.05 and a power of 80% and expecting a dropout of 20% of the patients, an adjusted sample size per arm of 164 patients is required.

Planned Outcomes

The primary outcome is a postoperative continence measured as 24-h pad test up to 12 months postoperatively. Secondary outcomes are potency, time of postoperative catheter removal, postoperative complications, and biochemical recurrence. The protocol for this randomized exploration study defines the conditions to assess the efficacy and safety of HAM application during RP in order to improve the postoperative functional outcome. This trial should pave the way for future studies of tissue engineering in an effort to reduce the morbidity of RP.

Trial Registration

Clinicaltrials.gov, identifier NCT03864939.

A single-center, retrospective review of robot-assisted laparoscopic prostatectomy with and without cryopreserved umbilical cord allograft in improving continence recovery

The objective of this study was to evaluate the safety and effectiveness of cryopreserved umbilical cord (UC) allograft as a nerve wrap around the neurovascular bundle (NVB) in accelerating return to continence after radical prostatectomy. A single-center, retrospective study was performed on 200 patients who underwent bilateral, nerve-sparing robot-assisted radical prostatectomy (RARP) with and without placement of UC around the NVBs (n = 100/group). Patients were excluded if they had previous simple or transurethral prostatectomy or history of pelvic radiation. Post-operative continence, defined as 0 or 1 safety pad, was analyzed between groups at 1, 3, 6, and 12 months. Complications, biochemical recurrence and adverse events were assessed to determine safety. Patients who underwent RARP with UC were significantly more likely to be continent at 1 month (65% vs. 44%, p = 0.018), 3 months (83% vs. 70%, p = 0.03), and 12 months (97% vs. 87%, p = 0.009). Sample stratification revealed that UC is beneficial for obese patients and those > 60 years, both of which are high risk for post-RARP incontinence. Biochemical failure was noted in 2 (UC) and 4 (control) patients. No adverse events or complications related to UC were observed. The results suggest that UC allograft is safe and accelerates continence recovery in post-RARP patients. Prospective, randomized trials are warranted.

Application of amniotic membrane in reconstructive urology; the promising biomaterial worth further investigation

Introduction: In reconstructive urology, autologous tissues such as intestinal segments, skin, and oral mucosa are used. Due to their limitations, reconstructive urologists are waiting for a novel material, which would be suitable for urinary tract wall replacement. Human amniotic membrane (AM) is a naturally derived biomaterial with a capacity to support reepithelization and inhibit scar formation. AM has a potential to become a considerable asset for reconstructive urology, i.e., reconstruction of ureters, urinary bladder, and urethrae. Areas covered: This review aims to discuss the potential application of human AM in reconstructive urology. The environment for urinary tract healing is particularly unfavorable due to the presence of urine. Due to its fetal origin, the bioactivity of AM is orientated to induce intrinsic regeneration mechanisms and inhibit scarring. This review introduces the concept of applying human AM in reconstructive urology procedures to improve their outcomes and future tissue engineering based strategies. Expert opinion: Many fields of medicine that have accomplished translational research have proven the usefulness of AM in clinical practice. There is an urgent need for studies to be conducted on large animal models that might convincingly demonstrate the underestimated potential of AM to urologists around the world.